Borehole inspection devices of this type, which are also called internal test sensors and also referred to below as devices for short, are used, for example, for borehole inspection in crankcases for internal combustion engines. They are used to image the radial inner surface of the borehole, and, based on the imaging using image processing and pattern recognition methods, to check whether the radial inner surface meets the predetermined requirements for surface quality.
Such devices are known from NO 2009/003692, DE 4416493 A1, DE 4320845 C1, and DE 3232904 C2, for example.
An imaging system for three-dimensional imaging of the interior of an object is known from US 2010/0048995 A1, and may be used, for example, in endoscope-based medical examinations. A medical endoscope is known from US 2014/0055982 A1.
An optical measuring device which operates according to the principle of white light interferometry for measuring surfaces of a measurement object is known from DE 10 2004 045 808 A1.
An interferometric measuring device for measuring the shape of a surface is known from DE 10131780 A1.
A borehole inspection device of the type in question for inspecting a borehole in a workpiece is known from DE 10 2009 019 459 B4, having a measuring head which is designed as an endoscope and is insertable into the borehole to be inspected and movable relative to the borehole in different axial positions, and which has an imaging optics with a panoramic view for imaging the inner surface of the borehole, the imaging optics being in image transmission connection with a digital image recorder. The known device also has a memory for storing the images recorded in different axial positions of the measuring head, and an evaluation apparatus for evaluating the images stored in the memory. The inspection device known from the cited publication allows boreholes to be inspected quickly and accurately.
Similar devices are also known from DE 10 2007 031 358 A1 and DE 10 2008 009 975 A1.